import java.util.Scanner;

public class JianFei {
    public static void main(String[] args) {
        /*
        int[] arr={21,24,33,28};
        int sum=0;
        for (int i=0;i<arr.length;i++){
            if (arr[i]%2==0){
                sum+=arr[i];
            }
        } System.out.println("sum="+sum);
            数组求和
         */
        int[] arr={39,27,48,17};
        Scanner reader=new Scanner(System.in);
        System.out.println("请输入一个数：");
        int num=reader.nextInt();
        int a=-1;
        for (int i=0;i<arr.length;i++){
                if (arr[i]==num){
                    a=num;
                    break;
                }
        }
        System.out.println("a="+a);
    }
}
